Phenotype of CD45RA⁺ and CD45RA^– CD4⁺CD25^high T cells in human adult peripheral blood. (A) Representative distribution of CD45RA expression among human CD4⁺CD25^high T cells from leukapheresis products (top panels) and coexpression of CD62L and CCR7 on the respective subpopulations (bottom panels). (B) Expression of FOXP3 (left panel) and CTLA-4 (right panel) in CD45RA⁺ (shaded histograms) and CD45RA^– (solid-line histograms) subsets of CD4⁺CD25^high T cells. Dashed-line histograms represent expression levels of the respective markers in CD4⁺CD25^– T cells. Numbers in dot plots indicate percent of cells within gates or quadrants.